Use LED as switch… (WRAP board)

  • Hi, how about this wacky idea…
    Use one of the LED's on the Wrap boards (or other hardware if unused LED's exist) as a switch connected to an opto-isolator.  -->(

    I remember seeing in pfsense some development on using the LED's on the Wrap boards.

    In the same way that a user can login and use the "wake on LAN" to start a computer, a link could be created that would flash or run continuously one of the LED's connected to an opto switch acting as a relay to...
    turn off/reboot an outlet with computers, or turn on/off a pump for the liquid helium that cools the small fusion reactor that powers your network of computers.  :o

    Fusion, fission, collapsing field magneto flux capacitor... whatever floats your boat  ::)

  • Nice idea!!

  • Surely one way to go.

    If you want to control your power plant it might be easier to use an ethernet based control system.
    eBay just had some Crestron QM-RMCs for cheap [a month or so ago](<br />). No fiddling around with solder irons etc. ;-)

    Actually, if I gave you the correct IP and port, you could control the lights in my office via a web browser already. Or the beamer, DVD player, …

    To me this would be kind of reinventing the wheel. It's already available as soft- and hardware for cheap.

  • Would be cool if there was a freebsd driver for this thingy: You could hook it up your pc or alix and switch power on 4 sockets or even programm schedules that the unit can perform on it's own. They are pretty cheap (around 30 euros here in germany). I use some of them in our serverroom to be able to reset some stuff remotely like dsl modems or things like that. Much cheaper like the ip-ones with integrated webserver.

  • I think there was once in "elektor" (german do-it-yourself-electronics-magizine) an article about how to make a small microcontroller based webserver with a few relais.
    Also i remember there where a few shops that sell these things as kit or already assembled for around 20€.

    But i like the LED approach :D
    We would have to ask Pascal Dornier which LED's he's using and then get a datasheet of them for the timing/max datarate.

    Maybe i'll do that after my semester-project is over ;)

  • The WRAPs and ALIXEs have a GPIO bus that you can connect via a jumperblock. It's probably nicer to use that connector instead of soldering on the led pins. It's all documented at Maybe you can come up with some small circuit to upgrade it and add some fancy stuff  :)

  • If you are trying to control power to a device you can use this device.  I have a dialup modem attached to a PC as a backup which allows me to login and I can power cycle my devices remotely.  Allows you to control up to 8 devices independently via the web interface.  They have extra modules for different functionality like pinging an IP and if there is no response for an extended period of time it will automatically power cycle the device.  The price is $109.00  which is nothing in comparison to the other devices out there!  Fan is a bit loud so I would recommend keeping this in a server room or a garage, basement…etc